


When you least expect it

by amamiya_toki



Series: Omurice, Tabasco, and Beer [1]
Category: IDOLiSH7 (Video Game)
Genre: Age Difference, Alternate Universe - Gender Changes, Dubious Consent, F/M, First Time, Nipple Play, POV Third Person, Sibling Incest
Language: English
Status: Completed
Published: 2018-04-08
Updated: 2018-04-08
Packaged: 2019-04-19 18:33:19
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 7,374
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14243295
Author URL: https://archiveofourown.org/users/amamiya_toki/pseuds/amamiya_toki
Summary: For the past few months, Nanase Riku had been feeling down. Her precious younger brother, Nanase Tenn, had been treating her coldly. Seeing how they used to be so close, this makes her feel troubled. If only she only knew the reason why he had been avoiding her. But, does she really want to know





	When you least expect it

**Author's Note:**

> I was supposed to take a week's hiatus from writing after finishing "Song of the Sun" but I ended up finishing this in four whole days, mostly evenings and time in between the day. I did a bit of writing for a few other things before that. I haven't started on those games I said I wanted to start yet.
> 
> I guess no matter what, writing has become a part of my lifestyle that I can't stop no matter how hard I try.
> 
> Anyway, today we have the beginning of the Riku-nee AU which I did a sampler of in February. Been dying to write this since back then, so I'm really glad I finally have the time to. Enjoy!

"A mixer?" Izumi Iori could not believe what he had just been told. "You, of all people?"

"It's the truth!" Nanase Riku, insulted by her childhood friend's reaction, pouted. "I got asked out by some guys from the seminar, along with Tsumugi-chan! Why do you have to make it sound like it's something bad? You're always like that! Iori you meanie!"

"What kind of childish insult is that? You're twenty, for goodness sake. And I was not implying that the fact that you got asked out to a mixer is a bad thing but was simply expressing my disbelief. To think that someone would consider you as attractive completely eludes me."

"Well, unlike you, I'm already an adult!"

"You say that you are an adult, but if you ask me you don't seem like one at all."

"Why is that so?!"

"Now now, Izumi-kun. You don't have to state it out so explicitly..."

"That would not do, Takanashi-san. As you would know, this person has little awareness of her status of being a woman. Her choice of clothes aside, doesn't her behaviour remind you of a child's?"

"What do you mean my choice of clothes? I do dress quite decently!"

"Decently, yes. But if you intend to make yourself look attractive to men, you should at least have a more mature appeal. Your childish mannerisms and behaviour would only be a turn-off. At least by dressing up more maturely, you would leave a lasting impression on them."

"But Iorin, Ricchan's clothes look like everyone else's. Isn't that what girls all wear nowadays?"

"You are not getting my point at all, Yotsuba-san. It's about sex appeal."

"Sex... appeal?" Riku cocked her head to the side, as she did not understand what Iori had implied by that.

"I think Iorin means that he doesn't think that you're sexy, Ricchan."

"I-I wasn't referring to myself! I was talking about it in general! In the first place, what kind of 20-year-old woman wears Omu-kun printed underwear?"

"What's wrong with Omu-kun, he's cute!"

"Riku-san, I believe that isn't the point..."

"Tsumugi-chan, tell Iori that he's a terrible person and I'm not going to talk to him!"

"I can hear you loud and clear!"

To distract her friend from the topic, knowing well that she would begin an argument with the dark-haired man if nothing was done, Takanashi Tsumugi offered a suggestion. "Say, Riku-san, do you have some time after our next class?"

"I do, but why?"

"I was thinking that we should go do a bit of shopping! It has been a while since we hung out together by ourselves after school, plus you said you wanted to take a look at dresses the other day. We could have crepes after that, too."

"That sounds fun! I'm in!"

"Crepes are nice, but I rather have pudding than crepes any day."

"Yotsuba-san, no one invited you."

The group of four friends had been having this conversation over lunch in the school cafeteria and all had classes right after their break, so they bid each other farewell before clearing the table and heading to class. Riku and Tsumugi were taking the same module for the afternoon's lecture, so once it was over they immediately set off.

They took their time looking at clothes from the many shops located in the fashion district and bought the crepes they wanted from a food van when they felt a little hungry. They continued window shopping after that, but before they left for home there was one particular destination Tsumugi wanted to bring Riku to.

"Riku-san, do you need to be home soon?"

"No, it's fine. Mom made dinner before leaving on her business trip, so I don't have to make dinner tonight."

"It must be tough, having both your mother and father absent from home due to work so often."

"You're the one who had it rough, Tsumugi-chan. You do all the cooking, cleaning and washing, don't you? Your father must be so proud of you!"

"I do it because I want to help him, that's why. But I've been a bit worried since he had been passing out drunk at the entrance of our home quite often recently. I know it's for work, but I hope he's taking care of himself."

"I see... oh, speaking of which, what kind of shop are we going to next?"

"It's just that one around the corner. You can see it soon."

If anything, Riku had not expected to be brought to a lingerie shop. That was why she had suffered some shock upon seeing the shop front and was showing some resistance while being pulled in by her friend.

"W-Wow..." was all she could manage, staring at the rows of lace and sheer and satin.

She could feel the heat on her face as she glanced at the shop's selection. Having only worn plain and simple bras, the assortment on display was something that was completely new to her.

"They're all so... bold. Do you wear this kind of thing every day, Tsumugi-chan?"

"Riku-san, this is barely what people would consider bold... can you see those at the far end? Those are what people call bold."

"Oh..."

Tsumugi had a point. Those had slits in them, at rather... well, inappropriate places, too.

But perhaps what made Riku embarrassed was the fact that she never really cared about what she wore under her clothes. It was not like she had a body that was too lanky or gawky. In fact, she was blessed with a nicely rounded figure, neither too thin nor plump, with well-defined curves at the right places. She also has a sizeable bust, although it causes her to suffer upper backaches at times.

After getting over her initial embarrassment of being in the shop, she began to look around. There were some that she thought were quite pretty, others on the cute side. She avoided the section with the skimpy ones on purpose, of course.

She eventually decided on two sets, which she thought would look quite nice on her. They were also quite reasonably priced, and she was able to pay for them for the money she initially set aside for the dress she had thought of buying. She even had some change left over to spend on something else, but she knew that she had spent enough for the month and chose not to use the money.

The two ladies parted after they bade each other farewell at the train station, as they lived in opposite directions.

As she had never attended a mixer before, her heart was beating with excitement. She loved meeting new people and talking to them, so such gatherings were of interest to her. However, because it was starting quite late in the evening, she was worried about leaving her younger brother at home alone.

Nanase Tenn was born five years younger than her, but they shared the same birthday. They had been very close as children, to the point that he always followed her around and was more upset about being separated from her than their parents as a toddler. Unlike her, he was smart and talented, maintaining good grades throughout his schooling years. He was in his final year of middle school now and was preparing to take exams for his high school of choice.

Since Tenn entered elementary school, their parents became absent from home more often due to work. That left the siblings alone at home and the time they spent together made them grow even closer. However, that changed over the past year or so.

In the past, Tenn would greet her with a hug whenever either one of them returns home at the end of the day. Now, he barely shares the same space as her. He would shut himself in his room unless it was for his meals and to use the toilet and bath, and brush her off coldly whenever she tries to speak to him. What made things worse was that she could not figure out why, or what had happened to him.

Just thinking about it made her heart sink.

She loved and cared for her adorable brother so much, since the day he was born. Yet he felt so much like a stranger to her now that she could not help but feel troubled and lonely.

"I'm home… oh." Just as she entered the house, she caught sight of her brother, who was coming down the stairs. From the pile of clothes he held in his hand, she could guess that he was about to take his bath. "I'm home, Tenn-chan."

"Welcome back, Riku-nee."

"Have you had dinner?"

"Yeah."

That was all he said before he walked off, not giving her the chance to continue the conversation.

As she had an assignment to finish for class the next day, Riku could not let herself feel upset by that. After leaving her belongings in her room, she went down to the dining room for dinner. Both parents would not be home until two days later, but her mother had prepared and wrapped a portion of her favourite omelette rice for dinner. The delicious smell of the dish made her stomach growl, and after reheating it in the microwave she began to tuck in.

When she had just finished doing the dishes, she heard the sound of footsteps from someone climbing up the stairs. That meant that Tenn was done with his bath, and she was free to take hers. However, because she just ate, she did not want to get in immediately.

Upon reaching her room, she got started on her assignment. She was about a third done with it when she received a message from Izumi Mitsuki, Iori's sister, asking if she was available to take over a morning shift on the coming Saturday at their family's shop. After checking her schedule, she noted that she had no plans for that day and agreed.

That was when she noticed that an hour had passed, and it was a good time to hop into the bath.

Aside from her towel, she brought with her the paper bag containing the two sets of lingerie that she had purchased. She wanted to try them out after the bath, to see how they would really fit on her.

Bathtime was her favourite time of the day. She hummed one of her favourite songs as she washed her hair and body, feeling the grime and sweat of the day be washed off by the running water. For a moment, while she was massaging her scalp, she felt like she heard the door outside open, but concluded that it was just her imagination.

However, it was only when she was done bathing and was drying off that she realised that she forgot to take a change of clothes with her. There was no way that she could go out naked or while wearing just a towel. She only had the two sets of lingerie with her, so she had no choice but to wear that.

She tried on the first set. It consisted of a lightly padded white T-shirt bra, the cups decorated with lace patterned with creamy yellow flowers. The panties were bikini-style, with the same lace as the bra cups at the front. The fabric at the back covered her entire bottom and was quite comfortable.

The second set she bought was more daring and had been recommended to her by the clerk from the shop. The top was a black bra, but unlike the first which she chose it was fastened in the front and was unpadded. Instead, the cups were only a thin layer of embroidered lace. While it revealed for an ample cleavage to show, it was enough to cover her breasts. However, because of the lace, she could catch glimpses of the pink of her nipples. The panties that came with it, also in black, was a thong. The straps were so thin that she was worried that they would break as she put them on. It was her first time wearing something this skimpy, and lack of coverage made her feel rather uncomfortable.

"As expected, I don't think these things really fit me..." She murmured, turning around in front of the mirror to see how the dark coloured fabric clung to her figure.

It was not that she looked bad in them. Rather, she was more than astonished to see how different she looked. When she celebrated her twentieth birthday a few months ago, officially becoming an adult, nothing felt different to her. In fact, life still went on the same way it always does. It is only when she had worn these, a completely different kind of underwear than what she had put on her entire life, that she became aware of her own body and begun worrying what others would think about her.

But, who could she ask for an opinion? There may not be of use getting another woman's opinion since she was more concerned about how a guy would think. She had male friends, but there was no way that she would let them see her wearing so little if it was not a swimsuit.

In her mind, there was one person whom she knew she could ask: her brother. They used to take baths together, at least until he began middle school, so she was comfortable with him seeing her bare so much skin. She was worried that he would kick her out of his room if she barged in, either because he did not want to talk to her or she may be disrupting his study time.

But this may be a chance for her to speak to him. She had always used excuses to avoid confronting him, but only because she was scared that it would make their relationship worse.

Perhaps if she tried harder to approach him, she may get him to tell her the reason why he purposely avoids her.

With that prospect in mind, she went out of the bathroom and headed up the stairs to his room. Much to her surprise, the door was not locked, and she turned the knob to enter without knocking.

"Tenn-chan, I wanted to ask—"

What she saw when she opened the door took her completely by surprise, to the point that she was shocked speechless.

Tenn sitting at his desk was not the part that was not the reason why she had been left stunned. Rather, it was what he was doing when she had opened the door that did.

The first thing that had caught her attention was what he had been doing with his right hand. The fingers of that hand were curled around his dick, which was sticking out of his unzipped pants. It was hard and erect, and the tip was glistening with pre-cum.

When she was finally able to push this sight to the corner of her mind and look up to look at Tenn's face, she spotted something too familiar in his other hand.

Were those not the pair of panties that she wore today, the yellow one with the red Omu-kun print?

How did he get those?

No, wait, that was not the matter at hand.

As dense as she was about many things, she was not completely ignorant about such matters.

She was aware that she had caught him masturbating. But, what does masturbating had to do with him stealing her underwear? Why was he holding them like that? What exactly was he using them for?

No. It cannot be... There was no way her adorable little brother would do something filthy like masturbate to her scent.

But if he did, why?

Why her?

No, this is not the time and place to think about these things

"I'm sorry for interrupti—" She tried to turn and escape, but she was grabbed and she was yanked back into the room.

The grip on her arm was so strong that she could not help but to let out a small cry of pain.

She heard the door of the room shut with a loud bang, and her back was slammed against it. Tenn placed his left hand against it, arm outstretched, to prevent her from escaping. Although they were about the same height, she felt like he was looking down at her. His glare was fierce, and it frightened her.

"I'm sorry, I'm sorry! I won't tell anyone what I saw, I promise!"

She did not know where to look, so she shut her eyes. If she looked straight, she would be looking into his eyes that seemed to be burning with fury. If she looked down, she could not ignore the sight of his exposed erection.

Was this person really her younger brother?

The adorable, cheerful child who called her 'Riku-nee' so lovingly with a bright smile?

Nothing made sense to her, at this moment. All she wanted to do was to escape, to avoid having to face him and the situation at hand. She hoped that, as long as she remained still and silent, he would back away and let her go.

But that did not seem to be the case, as he heard him let out a chuckle.

"To think that it is during this one time that I let my guard down and got careless that something like this happened. How very ironic, how very amusing..."

"Tenn... chan...?"

Much to her surprise, his tone did not reflect any sort of anger. If anything, he sounded hurt and in pain, and perhaps conflicted. But, why?

"But I didn't think that you would come into my room, wearing something like this." He trailed his right hand slowly up her left thigh, his touch sending shivers down her spine. He stopped at the curve of her hip, slipping his fingers into the space between her skin and panties to play with the thin band. "You just bought this recently, didn't you? It's not like you to buy something so daring. What's the occasion?"

Should she tell him honestly? She had no reason to lie, but she was not sure what would be appropriate to tell him in this situation.

"Y-You see, I got invited to a mixer... Iori said that I have no sex appeal, so I thought that... you know, if I wore something like this underneath my clothes I would seem more adult-like... or something like that..."

"Hmm..." He hummed in response to her answer. "I see. So that's how it is."

What did he mean by that? "S-Say, Tenn-chan, why are you doing this? You're not acting like yourself and it's scaring me."

"This is how I always am. You just don't know, Riku-nee."

"You're lying. The Tenn-chan I know has always been a sweet and gentle child. It must have been that much of a shock to you that you must be angry with me. I didn't do it on purpose, I swear."

"No, no, no. That's not it, Riku-nee. You don't understand anything... anything at all."

That statement made her even more confused than she already was. But he did not give her the chance to ask what he had meant, as he leaned forward to capture her lips.

Friendly kisses on the cheek used to be common for them when Tenn was much younger and smaller, but one on the lips was a first for Riku. The reality that it was her first kiss did not hit as hard as the fact that her younger brother was now kissing her, probably in the same manner as the scenes she watched in romance drama serials.

When they parted briefly she opened her mouth to tell him off. However, he did not give her the opportunity and resumed the kiss. He slipped his tongue into her mouth and began to kiss her roughly.

She tried to protest, but it was futile. Tried to push him away, but he was much stronger than his scrawny body implied he was. Then again, she found it hard to muster much strength, as she could not understand the mix of feelings that stirred in her chest.

This was wrong, she thought. They were sister and brother... siblings related by blood. They should not be doing things like this. Yet, despite knowing that, she found that she did not dislike being kissed by him. In fact, it felt good to her, so much so that she felt like she was going to melt.

She had heard that kisses were something amazing, and now that she had her first experience she could no longer disagree with that statement.

"!!" She could not suppress a yelp, although muffled by the kiss when she felt his hand cup her left breast over the bra.

He first gave the mound a light size squeeze, followed by another before his groping began to grow rougher. Just before he broke the kiss, he stopped so as to use his thumb to rub her nipples through the fabric. He first rubbed in a larger circle, then slowly focused more on her buds.

As she caught her breath, panting slightly due to the lack of oxygen, she felt a strange feeling begin to pool in her stomach.

"These are in the way." Tenn declared, pulling the delicate material of the bra roughly above her chest before she could stop him.

Now that it was removed, the bra could not do its job of containing her large breasts in them and they were now bare to his sight. She tried to use her arms to hide them, but he stopped her by grabbing hold of each arm and pinning them down against the door, as her back had been the entire time she entered his room.

Riku could feel her face redden.

Sure, this was not the first time he had seen her body exposed like this. But this was a very different situation that was far from innocent times that they shared in his childhood. It was because it was so different that she was scared of him, of this situation and what he had intended to do to her, which was still unknown.

"Tenn-chan, why are you doing this?"

"Isn't it obvious?"

"What do you mean? I don't understand what you're saying at all!"

"I'll make you understand, then."

He kissed her tenderly at the corner of her lips before lowering his head and body, so that his face was at the level of her chest. As he did so he loosened his grip on her arms, freeing them. But it was not to let her escape.

His left hand went straight for one breast, using the tips of his fingers to first gently caress her skin, over the areola and her nipple. The other one he took in his mouth, enveloping the pert bud in its wet warmth. He first prodded it with his tongue, then giving it a lick before sucking on it. A few moments after he began sucking, he changed the movements of his fingers. Instead of simply using them to stroke the pink bumps, he began to tease them roughly with pinches and tugs.

Each of his touches, rough or gentle, sent a tingling sensation through her body.

"Stop..." She had intended to say it firmly as a warning, but she could only manage so much as a whimper.

She had never felt anything like this before.

It was all so new to her, so strange, so foreign. Yet her body did not even try to reject it, even though she knew that she should stop him before it was too late.

"Tenn-chan, no, please, stop." She begged him. "This is wrong..."

"Wrong?" He looked up at her, in the eye, when he gave his reply. "I believe this is normal. After all, what kind of man would be able to resist and control themselves, when they see the woman they are attracted to appear in front of them wearing something that makes them look incredibly sexy?"

Sexy?

Her?

He actually thought of her as sexy?

"You... you pervert..."

"Look," With the other hand that had been left idle, he reached down between her legs, stroking the fabric of her panties with his index and middle fingers daintily. "All I did was play with your breasts, yet it's already so wet down here. Who's the real pervert here, hmm? The person who got aroused just by being touched by her little brother? What can you say about that, Riku-nee?"

"That..." She had nothing to say.

What could she say?

She was fully aware that the way he touched her had made her body react, perhaps instinctively, but not in that way. But she could not deny how good it had felt.

"Don't worry, Riku-nee. This is only the beginning. I'm going to make you feel a lot better than you already did."

Straightening his posture again, he held her by the wrist, pulling her towards his bed. He pushed her onto it, stripping himself of his long-sleeved T-shirt before leaning forward to bend over her. He hooked his fingers into the band of her panties, one hand on each side of her hip, and began to remove them. To prevent her from resisting, he forced her to ease her hips upwards.

Once removed, the fabric was discarded onto the floor.

She was now lying naked, on his bed, in front of him.

"D-Don't look..."

"Why? How could I not look at you? You're beautiful, Riku-nee. Very, very beautiful."

From her belly button, he ran his hand down her smooth, creamy skin to the folds in between her legs. He captured her lips for another kiss. As he did, he moved his thumb along the outer folds, gently massaging the sensitive area. She moaned lightly into the kiss when he found that little nub, tapping it lightly with a steady rhythm with his forefinger.

It was only a series of light touches, but she could feel a small fire start to burn in her body as he continued to tease it. Those little jolts of pleasure soon became sparks that exploded like fireworks, as he began to rub it roughly with two fingers in a circular motion. The fire burst into a blaze of heat that erupted in her groin.

She broke the kiss, her mind starting to cloud with the overwhelming sensation. "Te-Tenn-chan, no, not there!"

"There, you mean, your clit?" He gave it one hard squeeze, which made her cry out in both pain and pleasure. "It seems that you're really sensitive there... perhaps this is your first time? Or, is it not?"

"Of course it's my fir—" She could not continue her sentence, as she could not hold back the loud moan that escaped from her as the heat reached its peak.

She felt a wave of pleasure overcome her, the heat rising high from within her abdomen and spreading throughout her entire body. For a moment, Her body tensed up for that brief moment, and after that, it relaxed, and she found herself panting slightly as she lay weakly on the bed.

Just... what was that feeling?

It was... good.

So, so good.

So much so that it made her a little scared, as she had not experienced anything like this before.

"Did you come, Riku-nee?"

"Come...?"

That was what it was called? It felt so incredible.

But it was not enough. She wanted... needed more to satisfy her.

"That face you're making now... it's so cute. So adorable that I want to make you mine and mine alone."

He kissed her again before dragged his fingers lower. They slid down easily along her skin that had been slicked with her fluids and found her entrance easily. He eased one finger in, pushing it in as deep as it could go.

The sudden, unexpected intrusion made her stiffen up instinctively. She raised her hands to her face to cover it from Tenn's sight.

She was naturally sensitive, but because she had just come, she was even more so than before

"Ahh, it's so wet and warm in here... what a delightful feeling." Tenn then whispered into her ear, as he moved his finger in and out of her at an agonisingly slow pace. "Say, Riku-nee, you were expecting to do this kind of thing with some guy you'd meet at the mixer, won't you? You were trying to dress up so that you would get your pussy creamed, weren't you? What a naughty little slut you are,"

"No... no, that's not..."

"Why don't you choose me instead? I'm sure that I would be able to satisfy you, and give you more pleasure than anyone ever would."

When Tenn removed his finger, she let out a small whimper. However, there was a short pause and the sound of clothes rustling. She then felt something hard rub against her folds, and it was long. It could not be... could it?

She peeked through her fingers to confirm her suspicions, and she was right.

Tenn, now as naked as she was, was rubbing the length of his erection against her entrance. She could feel how thick his girth was, and how it was hot and throbbing as it rubbed against her most private spots.

For a moment, she imagined how it would be like if something that big entered her. Would it feel as good as the finger? Or would it hurt instead? It was so long and thick... would it even fit inside of her?

But, even if she was a bit of an idiot, she knew what that thought and act implied. That was why she could not allow him to do what he pleased any longer.

If he did... they would not be able to return to being normal siblings anymore...

"Tenn-chan, that's... we can't..."

"You say that, but you want this inside of you, don't you? This hot, hard, thick rod of mine... you want it pumping in and out of you, bringing you a new wave of pleasure that you never felt before. Am I wrong?"

"You're only fifteen, and my little brother!"

She tried to push him away, only to have him grab her wrists with one hand and hold them high above her head.

"So, what?" She did not expect him to react that way, and it had taken her by surprise. "I may only be fifteen and am your younger brother. But I believe I am just as much as a man than any other, and am the only capable of giving you the pleasure that."

"Tenn-chan..."

"Still calling me by that name, are you? It seems that I'll really have to teach you, then, that I am no longer the child who is simply satisfied by being able to follow behind you."

With his free hand, he guided his erect dick to her entrance. Riku clenched up as she felt the head prod the opening, but he did not enter her just yet.

"If you don't relax, it's going to hurt."

That was the only warning he gave before he pushed it in. It was, indeed, big and her cry of pain was almost like a scream. There were only the two of them in the house, so there was no one else who would have heard her. Tenn, however, ignored her as he slowly eased his entire length in. Riku's pants began to grow heavier as she left him to go deeper and deeper into her.

This cannot be happening, she thought as a few tears escaped the corner of her eye.

At first, it had just been her first kiss... and now, her virginity that had been taken from her forcefully by him.

She could no longer hope to become a bride, to be able to wear that beautiful white dress and walk down the virgin road. It was her dream, ever since she was a child, and now it had been crudely shattered.

In spite of that, she still could not hate him.

Even now, she could only feel love for him. No matter what he had done, or what kind of terrible person he had become. It was not because he was her younger brother, but because it was him.

But, despite that fact, the pain was just too much.

"It hurts... it hurts a lot, Tenn-chan..." She began to sob, her tears welling up and overflowing. "Please, stop this... take it out... I beg you..."

"That's why I told you to relax, didn't I?" He pressed a kiss to her sweat-stained temple, then to her cheek. "But, don't worry. I'll make you feel better soon."

He was right. The pain did begin to die down, albeit rather slowly. As it did, her pants grew lighter as well.

Tenn waited for her breathing to become steady again before moving. However, he did not give her a warning or asked if she was ready before he slowly withdrew. As the base of the head emerged, he rammed it back in, all the way into her deepest areas.

"Ah!"

The first thrust was electrifying.

He had gone so deep inside her that she thought that she could feel him hit her womb. It had made stars dance across her vision, and her voice could no longer be suppressed.

However, Tenn did not stop with just one, and he continued to move in and out of her at a rough and messy pace.

"Ahh, Riku-nee... my Riku-nee... we've finally become one..." He was chuckling as he tore her apart, making her mewl with a newfound pleasure as he rubbed against her insides with his dick.

Her inner walls were incredibly moist and hot. Yet, the heat was comfortable and welcoming to him. But what Tenn loved the most was the way they squeezed down on his erection, as if they were milking him for his cum.

"Riku-nee, you're so tight... what a lovely feeling. I could get hooked on this."

He had always wanted to violate his sister like this.

It was in his final year of elementary school that he realised that his growing affections for her, who was five years older than him, was something that was not normal. Yet he was still naive innocent at the time, thinking that he would be satisfied as long as he got to spend time with her.

However, things changed when she began university.

No one had expected her to get in, with her bad grades. To help her study, he even spent extra time in his first year of middle school learning the material from high school in order to teach her the topics she was struggling with. But after she started, she became more busy, not just with assignments and reports but also with maintaining her social connections.

Despite having friends of his own, the fact that his beloved sister was spending less time with him made him feel lonely. It also made him unusually frustrated and angry, but he was not sure why he felt this way.

It was during the latter half of his second year of middle school that he finally understood.

At that time, some of his classmates snuck in erotic magazines, the kind with female models in skimpy swimsuits and suggestive poses. He caught a glimpse but had no interest in any of them. Yet when he returned home that night, he had a strange reaction when he accidentally opened the bathroom door to see his sister changing out of her clothes before taking her bath.

He ran straight to his room after that, slamming the door behind him. His groin felt funny, and when he examined it he noticed that his penis had been erect. He had known about this, having heard it from his classmates, but it was his first time experiencing it.

He knew he had to touch himself in order for it to return to its original state. It tingled when he touched it, but managed to grip it in his fist.

Think of something sexy, was the suggestion he remembered being given. The only thing that came to mind was his naked sister. It was not long before he ejaculated, over his hand and staining his underwear.

It was clear to him after that day that he no longer so her as his sister, but as a woman. A target of romantic affection and sexual attraction.

Perhaps because of how he felt towards her, he had found it frustrating how she had failed to realise his feelings and continued to treat him like a child.

However, he soon discovered that he would feel aroused not just by thinking about her, but from her scent alone. It became increasingly painful to control himself whenever she was near him, and his occasional nightly masturbation sessions increased in frequency.

This would certainly not do, as he felt like he would lose his mind if he continued.

In the end, he decided that it was best that he put some distance between the both of them. That was why he had started avoiding her and treating her coldly, to make her avoid coming into contact with him.

That plan flopped, of course, when she barged into his room earlier this evening. But when he heard that she was going to a mixer, he could not control himself any longer.

There was no way he would give her... his woman up to anyone.

He was aware that what he had done may hurt her, but he was much too desperate. He needed to make her his, in any way he possibly can.

That was just how much he loved her.

"You know, Riku-nee..."

"W-What?"

"I was just thinking how nice it would be if you could bear my children. That way, no one would ever dare to go near or touch you, much less try to take you away from me. You will be mine, forever."

"C-Children? What are you..."

"You mean you haven't noticed that I didn't put on a condom? I didn't have any in the first place, seeing how I didn't expect to have my dream of being able to fuck Riku-nee come true so soon. But you don't have to worry about anything. I'll take responsibility and look after the child with you, so all you have to do is to get knocked up with my baby batter. It's as simple as that."

For Riku, that was it.

She had already endured so much, and now he wants to make a baby with her?

Screw that, that was not what she wanted.

She did not want any of this to happen at all, in the first place.

"No... No, I don't want that. I'm not ready for this... for any of this. Why are you being so mean to me, Tenn-chan? What did I do to you to deserve this? If I made you angry or upset, I'm sorry. I'm sorry... but, please, anything but a child. I don't want to be a mother... don't make me a mother not this soon..."

She had broken down completely, and could no longer hold back the dark stormcloud that was her feelings that had accumulated within her.

Tenn, who had been driven by his emotions all this while, finally realised that what he had been doing and thought had been right was wrong.

"Riku-nee... please don't cry." He stopped his hips and let go of her wrists so as to be able to cup her cheeks with both hands, wiping her tears away as he placed small kisses on her face. "I said too much, I'm sorry. Don't cry anymore, I beg you. I love you."

"I love you too, Tenn-chan." She managed through her sobs, wrapping her arms around his neck and leaned up for a small peck on the lips.

Tenn, surprised by her confession, returned her quick kiss with his own.

"I won't do it inside you, I promise. So, please don't hate me. I love you so, so much."

"How could I ever come to hate you? You're so precious and important to me. That's why I can only love you."

"Riku-nee..."

She freed her hold on him and took his hands in hers, lacing their fingers together. "Let's continue. I want you to make me feel really good."

She wrapped her legs around his hips with a light squeeze, inviting him to grind even deeper into her. Perhaps it was her imagination, but she felt him get a little bigger, as he started to thrust in and out her again. This time, he steadily increased the pace of his thrusts.

"How do you like this, Riku-nee?"

"It feels... wonderful. It's my first time, but it's making me feel so good that I'm about to lose my mind."

"It's the same for me. It feels so good, more than earlier. Maybe because I'm so happy right now. I think I'm going to be close, soon..."

"Same. It's the same for me, Tenn-chan."

They rode the wave of pleasure that began to slowly rise up, higher and higher until it was about to hit its peak.

Riku came first, calling out his name in a soft cry as she came for the second time. Tenn groaned as he felt her clamp down on him even harder, and he knew that he, too, was about to come.

He managed to pull out of her just in time before he ejaculated, shooting his white cum over her groin. He felt his body weaken and he collapsed onto her. She wrapped her arms around his thin frame, embracing him tightly.

"Riku-nee, can I kiss you?"

"You're only asking that now?"

"I felt it was appropriate to do so, at this moment…" He blushed, averting his gaze from her in his embarrassment. "So... can I?"

"Of course you can, you silly boy."

With her permission granted, Tenn wasted no time in capturing her lips with his. It was a slow, tender kiss that was unlike any of those they had before.

"So, does this make us lovers now?" Tenn asked, his expression reflecting a bit of his still-childlike self.

"Lovers?!" Riku repeated after him, surprised.

"Of course. That was what I meant when I said that I loved you. Siblings don't do things like this, you know."

"O-O-Oh." Her face reddened.

Lovers… huh…

She did not dislike the sound of that.

"Pfft." She heard Tenn chuckle and gave him a confused expression. "I'm sorry. That expression you are wearing now is just so adorable that I couldn't help it."

"The cute one here is Tenn-chan!"

"No, it's most definitely you, Riku-nee."

"Stop laughing!"

That little quibble aside, the two decided it was time to get cleaned up. They took a shower together and changed into their pyjamas. By that time, it was late and they had school, hence classes, to attend the next day.

However, Tenn had one last request for his sister before they bade each other good night.

"Can we sleep together?"

It was something that he had not asked her in a very long time, and she was more than happy to oblige.

They got in under the covers of her bed, snuggling up to each other's warmth. It had been a while since Riku was able to hold her precious younger brother against her soft body, and for Tenn, to be able to feel at ease and secure in the sanctuary of her arms that were wrapped around him.

Before they knew it, they fell fast asleep, just like that.

And when they woke up the next morning, the sight of each other's face was a reaffirmation that what had happened yesterday was neither a dream nor a fragment of their imagination.

But none of that mattered now.

For the first time in what felt like forever, they smiled at each other as they wished their special person a heartfelt good morning before getting out of bed. It was the best way they could ever want to start their day.

Bathed in the warm sunlight, they knew that their days together had just begun.

**\- end -**

**Author's Note:**

> To note, Riku didn't go to the mixer in the end.
> 
> Also Tenn watches too much porn.


End file.
